1. Field of the Invention
This invention relates generally to implantable medical devices and, more particularly, to a firmware architecture permitting modular feature design for implantable medical devices.
2. Description of the Related Art
Since the introduction of the first implantable pacemakers in the 1960s, there have been considerable advances in both the fields of electronics and medicine, such that there is presently a wide assortment of commercially available body-implantable electronic medical devices. The class of implantable medical devices now includes pacemakers, implantable cardioverters, defibrillators, neural stimulators, and drug administering devices, among others. Today""s state-of-the-art implantable medical devices are vastly more sophisticated and complex than earlier ones. Today""s state-of-the-art implantable medical devices are capable of performing significantly more complex tasks. The therapeutic benefits of such devices have been well proven.
As the functional sophistication and complexity of implantable medical device systems have increased over the years, it has become increasingly useful to include a system for facilitating communication between one implanted device and another implanted or external device, for example, a programming console, monitoring system, or the like. Shortly after the introduction of the earliest pacemakers, it became apparent that it would be desirable for physicians to non-invasively obtain information regarding the operational status of the implanted device, and/or to exercise at least some control over the device, e.g., to turn the device on or off or adjust the pacing rate, after implant. As new, more advanced features have been incorporated into implantable devices, it has been increasingly useful to convey correspondingly more information to/from the device relating to the selection and control of those features.
In particular, implantable pacemaker therapies have grown in number and complexity. In conventional devices this growth in the number and complexity of the various implantable pacemaker therapies has led to numerous feature interactions. These feature-to-feature interactions may adversely affect the efficacy of various of the implantable pacemaker therapies.
For example, in conventional implantable pacemakers, various therapy algorithms write to the same memory location associated with a temporary parameter related to the beat-to-beat control of the implantable pacemaker. These temporary parameters may include Temporary Lower Rate Interval (TEMP LR INT), Temporary Pacing Atrial Ventricle Interval (TEMP PAV INT), Temporary Sensing Atrial Ventricle Interval (TEMP SAV INT), Temporary Post-Ventricular Atrial Refractory Period (TEMP PVARP), and the like. In conventional implantable pacemakers, the last algorithm to write to the memory location xe2x80x9cwonxe2x80x9d (controlled the setting of the parameter value). Because of this, feature interactions are difficult to manage in conventional implantable pacemakers. Typically, multiple therapy features, such as Mode Switch (MS) and Rate Drop Response (RDR), are not able to operate at the same time. To resolve adverse feature-to-feature interactions, specific features are typically forced xe2x80x9coffxe2x80x9d (either by the programmer or within the conventional implantable pacemaker) when another feature is turned xe2x80x9con.xe2x80x9d Additionally, these complex feature interactions, particularly in brady and tachy devices, lead to slow and difficult development of feature addition, modification and/or removal, because the features are not modular and cannot easily be added, modified and/or removed from a conventional implantable pacemakers during development.
The present invention is directed to overcoming, or at least reducing the effects of, one or more of the problems set forth above.
In one aspect of the present invention, a device is provided, the device comprising an implantable medical device and a controller controlling the implantable medical device, the controller having a plurality of modular features and having a firmware architecture allowing modular feature design and implementation, the firmware architecture coordinating between and among the plurality of modular features to reduce feature-to-feature interactions. The device also comprises the controller having a converter enabling efficient conversion between at least one identifiable first modular feature working in a rate domain and at least one identifiable second modular feature working in an interval domain.
In another aspect of the present invention, a method is provided, the method comprising controlling an implantable medical device using a controller having a plurality of modular features, the controller having a firmware architecture allowing modular feature design and implementation, and coordinating between and among the plurality of modular features to reduce feature-to-feature interactions. The method also comprises identifying at least one first modular feature working in a rate domain and at least one second modular feature working in an interval domain, enabling efficient conversion between the rate domain and the interval domain.
In yet another aspect of the present invention, a device is provided, the device comprising means for controlling an implantable medical device using a controller having a plurality of modular features, the controller having a firmware architecture allowing modular feature design and implementation, and means for coordinating between and among the plurality of modular features to reduce feature-to-feature interactions. The device also comprises means for identifying at least one first modular feature working in a rate domain and at least one second modular feature working in an interval domain, enabling efficient conversion between the rate domain and the interval domain.